Supplementary Provisions, Article 15
第十五条
The amount of insurance premiums that a class 4 insured person who, before January 1, 1970, prepaid insurance premiums for a period on or after that day is to additionally pay for each month of the period covered by the prepayment is, for each month of that period, the amount obtained by deducting, from the amount of insurance premiums that would be payable under the provisions of the Employees' Pension Insurance Act as amended by this Act if the person had not made the prepayment, the amount of insurance premiums that would be payable if the provisions of that Act prior to its amendment by this Act were applied.
昭和四十五年一月一日前に同日以後の期間に係る保険料を前納した第四種被保険者が当該前納に係る期間の各月につき追加して納付すべき保険料の額は、当該期間の各月につき、その者が前納しなかつたとしたならば、この法律による改正後の厚生年金保険法の規定により納付すべきこととなる保険料の額からこの法律による改正前の同法の規定を適用したとした場合において納付すべきこととなる保険料の額を控除した額とする。
In the case where the amount of an employees' old-age pension is calculated for a person who has the period prescribed in the preceding paragraph, if there is a month for which insurance premiums were not paid in the amount prescribed in that paragraph, the amount specified in Article 43 of the Employees' Pension Insurance Act (including as applied pursuant to Article 44, paragraph (1) of that Act) or Article 9, paragraph (1) of the Supplementary Provisions of that Act is, notwithstanding those provisions, the amount obtained by deducting from the amount prescribed in those provisions the amount obtained by multiplying 150 yen by the number of months of the insured period for the month for which the insurance premiums were not paid.
前項の期間を有する者について、老齢厚生年金の額を計算する場合において、同項に規定する額による保険料の納付が行われなかつた月があるときは、厚生年金保険法第四十三条（同法第四十四条第一項において適用する場合を含む。）又は同法附則第九条第一項に定める額は、これらの規定にかかわらず、これらの規定に規定する額から百五十円に当該保険料の納付が行われなかつた月に係る被保険者期間の月数を乗じて得た額を控除した額とする。
The provisions of the preceding paragraph apply mutatis mutandis to a person who has the period prescribed in Article 32, paragraph (1) of the Supplementary Provisions prior to their amendment by the provisions of Article 108 of the Supplementary Provisions of the 1985 Amendment Act (hereinafter in this paragraph referred to as the "supplementary provisions before the amendment"), in the case where, when the amount of an employees' old-age pension is calculated on the basis of the portion of that period that is deemed, pursuant to the provisions of Article 47, paragraph (1) of the Supplementary Provisions of that Act, to be a period of having been an insured covered by employees' pension insurance, there is a month for which insurance premiums were not paid in the amount prescribed in Article 32, paragraph (1) of the supplementary provisions before the amendment.
前項の規定は、昭和六十年改正法附則第百八条の規定による改正前の附則（以下この項において「改正前の附則」という。）第三十二条第一項の期間を有する者について、当該期間のうち同法附則第四十七条第一項の規定により厚生年金保険の被保険者であつた期間とみなされた期間に基づいて老齢厚生年金の額を計算する場合において、改正前の附則第三十二条第一項に規定する額による保険料の納付が行われなかつた月があるときに準用する。